1. Field of the Invention
The present invention relates to a system for controlling fuel injection in an internal combustion engine, more particularly to a flow control device used in such a system to control fuel injection timing, a fuel injection rate, or a fuel injection amount.
2. Description of the Prior Art
In an internal combustion engine, particularly a diesel engine, precise control of fuel injection is necessary to attain optimal performance for every engine operational condition. To attain this, it is advisable to electronically control fuel injection timing, fuel injection rate, and fuel injection amount. In this case, an electrically operated valve device such as an actuator is necessary.
Prior art electrically operated valve devices, however, have not had sufficient volume to effect direct control of fuel injection. Increase of the volume of such prior art devices, however, slows down the operation of the device and, thus, affects the quick control ability of the device, the object of use of such an electronic system.
To counter this, use has been made of a large volume fluid pressure servo-valve controlled by a small electric valve. This prior art, however cannot effect sufficiently fine adjustment of fuel injection, such as the control of the injection rate.